1. Field of the Invention
The invention relates to a moisture meter of the type for surveying applications in which the meter is hand-held and, in use, is held so that a sensor attached to it is in contact with the material being surveyed.
2. Prior Art Discussion
While such meters are generally quite accurate, they suffer from a lack of versatility because they are configured for only one type of material and calibration for variations of material is difficult for the user. Also, it is necessary for the user to note down on paper readings from the dial, which is time-consuming and difficult in some environments such as attic spaces.
Objects of the Invention
It is therefore an object of the invention to provide a moisture meter which may be used with a wide range of different materials.
Another object is to provide for capture of moisture information in a more simple manner.
A further object is to provide for more accurate determination of moisture content.
According to the invention there is provided a moisture meter comprising a hand-held housing supporting a moisture sensor of the type for contact with a material being surveyed, an output interface, and a controller comprising means for determining moisture content data according to signals from a moisture sensor drive circuit and for outputting said data at the output interface, wherein:
the meter further comprises a user input interface,
the controller comprises means for selecting stored material parameter values in response to user inputs, and
the controller comprises means for performing data processing with said selected parameter values to determine moisture content of a material in contact with the moisture sensor.
In one embodiment, the controller comprises an analogue to digital converter for conversion of analogue signals from the moisture sensor drive circuit.
In one embodiment, the controller comprises means for setting gain values for the moisture sensor drive circuit according to the selected material parameter values.
In one embodiment, the controller comprises means for setting gain values by setting gain switches connected to a filter/amplifier/detector stage of the moisture sensor drive circuit.
In another embodiment, the filter/amplifier/detector stage is connected to a logarithmic amplifier comprising means for linearizing the exponential form of a signal from said stage and providing an output signal to the controller.
In one embodiment, the meter further comprises a temperature sensor and the controller comprises means for performing compensation according to a sensed temperature value.
In one embodiment, the controller comprises an analogue to digital converter and comprises means for correcting the output of said converter according to sensed temperature.
In a further embodiment, the controller is connected to a memory storing a library of material types and associated parameter values.
In one embodiment, the input interface comprises a key dedicated to each of a plurality of material type groups.
In one embodiment, the groups include wood, wall, and roof material types.
In one embodiment, the input interface comprises a scroll key and the controller comprises means for scrolling through library items in response to said scroll key.
In one embodiment, the controller comprises means for storing each moisture reading.
In one embodiment, the controller comprises means for storing each moisture reading as a discrete record within one of a plurality of files.
In a further embodiment, the controller comprises means for automatically writing material type, date, and time data to each record.
In one embodiment, the controller comprises means for communicating with a host computer via a bidirectional port.
In one embodiment, the controller comprises means for downloading updated material parameter values from a host computer.
In one embodiment, the controller comprises means for uploading data records to a host computer.
In one embodiment, the controller comprises means for automatically writing a temperature value for a reading to the associated data record.
In one embodiment, the meter housing comprises a non-removable cover adjacent to a side edge of a circuit board contained within the housing.
In another embodiment, the cover has an aperture for access to an interfacing device of the meter.
In one embodiment, the cover is in a top side of the meter housing.
In one embodiment, the cover comprises a pair of opposed snap-fitting tabs engaging behind corresponding receivers in housing main body.